Reasons for back focus problems

[Pedro]

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Since I bought my M8 I had back focus problems with all lens I have purchased (35 f2; 90 f2).

 

Due to outstanding Leica customer care in Portugal I did not suffered much because they lent me a replacement lens while mine was being repaired at the factory.

 

Is this a recent issue (i.e. from the last couple of years) or this problem is typical of the Leica products? This issue was already well known before the M8?

[glenerrolrd]

Pedro If both the 35 and the 90 back focus ..it may be your M8 . You will find many threads about the back focus issue and rangefinder calibration. The best way to test is to try your lenses on another M8 ..if they both back focus it is most likely (but not certain) the body. Some users have had good luck adjusting their own cameras and with the M8 you can test and get immediate feedback. There is a lot written about this as with the M8 calibration problems are much easier to identify..so lenses that were acceptable on film may now be considered a problem. The lenses that frequently require adjustment are the Summiluxes (35/50/75) and the Noctilux. These also exhibit some focus shift(back) as you stop down ..so you need to be either exactly in focus at full aperture or even a little front focused wide open (1.4). If the problem is really with the lens then its more difficult and frequently has to be done in Solms. But I would encourage you to read the threads on calibration of the rangefinder. Roger

[ho_co]

Pedro--

I'm not sure, but I believe that one person who had his bodies and lenses checked in his presence by Leica USA said that Leica generally considers the 90/2 the 'gold standard.' That is, if I recall correctly, it generally gives the fewest problems.

 

The 35/2 is generally also not a trouble-prone lens.

 

So, as Roger said, you should consider the possibility that the problem might be with the body.

 

There have been a lot of threads on backfocusing, and a slow growth in our understanding of why some lenses seem to backfocus on the M8 but didn't seem to do so on earlier cameras; and it took Leica some time to begin to realize that some of the methods that worked previously for testing bodies and lenses are no longer adequate to the standards of the M8.

 

So I second Roger's suggestion that you do a bit of reading on the forum, and that you might also want to do a careful test of your lenses against a second M8 body to try to discover for sure whether any improper adjustment lies with the lenses or the camera.

 

If there is one thing the M8 has taught us, it is that it is a superb tool for optical discovery!

 

--HC

[Pedro]

I am sure the body is OK because while I used the replacement 35mm f2 (while mine was repairing) the focus was perfect. Now mine returned from the factory, repaired, and focusing perfectly.

 

Lets see what Leica will tell about the 90mm (I still do not have feed back).

 

What amazes me is that, with film, clients would not notice this issue (unless for some reason Leica is loosing quality and this is a recent problem).

[Philippe D.]

Hi Pedro,

What amazes me is that, with film, clients would not notice this issue (unless for some reason Leica is loosing quality and this is a recent problem).

It is not a loss in quality, in the contrary, it's a gain.

Just because the sensor is perfectly flat, and much more sensible and non tolerant as film are, you notice this back focus on digital but not on earlier cameras.

[doubice]

What amazes me is that, with film, clients would not notice this issue (unless for some reason Leica is loosing quality and this is a recent problem).

 

In the film days I would get my holiday slides back from developing and comment "I guess I did not focus that one right" , assuming it was my mistake, not the camera's......

 

In today's digital world, the gratification or disapointment is immediate. And we can pixel peep!

 

Digital sensors are flatter and thus much more sensitive to focus misalignment than film. A film emulsion has a certain thickness and as long as the image was focused 'somewhere within the emulsion', the picture was 'sharp'.

 

All the best,

 

Jan

[Pedro]

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Thank you all for the feed back!

[NZDavid]

<Is this a recent issue...or this problem is typical of the Leica products?> Not sure if this is much help, but no, it isn't typical of Leica. Nikon users at the newspaper where I work reported this problem a few years ago. It seems to be typical of digital cameras. If you can find a fix, stick with the camera, it will be well worthwhile.